The disclosure that some pills found at Prince's Paisley Park home and studio were counterfeit and contained the powerful synthetic opioid fentanyl strongly suggests the pills came to the superstar musician illegally.

Some of the pills taken from Prince's estate in Paisley Park after his death were counterfeit drugs that actually contained fentanyl -- a synthetic opioid 50 times more powerful than heroin, an official close to the investigation said.